If you look at a page that has something embedded from another website – most likely a Slideshare.net slideshow or a YouTube video – those third-party websites will probably drop some cookies on you just to track (I guess) what you’re watching and that it’s from my website.
You can stop your browser accepting cookies completely if you really want to (in the settings most probably). That shouldn’t affect you being able to use my website (though the embedded slideshows/videos might not work). You might not be able to leave comments on my posts – if you find that’s a problem, just tweet me your comment instead. 🙂